Fuel supply system



E. o. WIRTH'ETAL Dec. 14, 1948. FUEL SUPPIY SYSTEM 3 Sheets-Sheet l Filed Aug. 6, 1945 fmmj mi /MVENTOE o o y FH E RT m A@ 0 BW.T m. v QOA m. Md ma F v a Dec. 14,1948. EQMRTHETAL 2,456,605

FUEL SUPPLY SYSTEM i Filed Aug. 6, 1945- 3 Sheets-Sheet 2 ISO IB I9 ISG a ISO plc 5 l v NVE/wm :4E- Jang BAzPoo By @ML o. wnzTH ATTDK/VE Y Dec. 14, 1948.

Filed Aug. 6, 1945 E'. o. wlRTH ETAL FUEL SUPPLY SYSTEM ZAC,

3 Sheets-Sheet 3 FIC. 9

INVENTUR. FREDEZIK MRF-OD BY EMEL O. WIRTH AT'TQRNEY Patented Dec. 14, 1948 FUEL SUPPLY SYSTEM Emil O. Wirth and Frederik Barfod, South Bend, Ind., asslgnors to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application August 6, 1945, Serial No. 609,230

This invention relates to fuel supply systems or devices for internal combustion engines, and more particularlyto devices or systems in which liquid fuel is supplied under positive pressure.

An important object of the invention is to provide a fuel feeding system in which the fuel flow is automatically regulated in accordance with eertain engine variables such as, for example, engine speed and engine charging pressure.

Another object of the invention is to provide a generally new and improved fuel supply system for automatically controlling the fuel to air ratio under various engine operating conditions and which will provide improved fuel distribution to the engine.

This fuel supply system, while especially applicable to fuel supply systems of the character hereinafter particularly described, is not limited to such uses, but is obviously available, with or without modification, in a great variety of cases Where fuel is intended to be supplied `under more or less analogous conditions in an yinternal combustion engine or other fuel consuming device.

Further objects and advantages of the invention will be apparent, to those skilled in the art, from the following detailed description, taken in connection with the accompanying drawing. Although but one embodiment is shown, skilled persons will understand that many variations may be made without departing from the principles disclosed, and I contemplate the employment of any structures, arrangement, or modes of operation that are properly within the scope of the appended claims.

In the drawings:

Figure 1 is a diagrammatic view of an engine fuel system embodying the present invention;

Figure 2 is a diagrammatic sectional view of the fuel distributor shown in Figure l;

Figure 3 is a section taken on line 3--3 of Figure 2;

Figure 4 is a section taken on line 4-4 of Figure 3;

Figure 5 is a diagrammaticl sectional view of an alternative fuel distributor arrangement;

Figure 6 is a diagrammatic sectional view of the fuel nozzle shown in Figure 1; I

Figure 7 is a section taken on line l--1 of Figure 6; and

Figures 8 and 9 are sectional views of alternative types of fuel nozzles.

In Figure l there is shown an induction passage I0 having an air inlet I2, and an outlet I4 connected to the intake manifold I8 of an internal combustion engine, not shown, or to a super- 19 Claims. (Cl. 123-119) charger inlet, should a supercharger be used, the induction passage I0 being controlled by a throttle valve I8. A supercharger might alternately be connected to the inlet I2 or such a device might be connected to both the inlet I2 and an outlet I4. Liquid fuel is supplied by a pump, indicated generally 'at 2li, which may be operated by the engine, or by any other suitable means, and ls capable of supplying fuel under positive, preferably but not necessarily substantially constant, predetermined pressure. This pump may be of any well known type but, as shown, isV of the sliding vane type having an inlet 22 receiving fuel from a. source, an outlet conduit 24 and a bypass 28 vcontrolled by a pressure responsive valve 30. Fuel from the pump is delivered from the pump outlet conduit 24 to a passage 32 which communicates with a passage 33 connected with a chamber 34 in a casing 36, the fuel pressure in said chamber 34 being at all times substantially the same as that in passage 33, and this pressure in said chamber and passage being hereinafter in chamber 54 and passage 52 posterior to .iet 55 referred to as pressure A or control pressure. One Wall of chamber 34 is closed by a exible diaphragm 38 which is marginally clamped between the casing 36 and a shoulder of the body 4D of the device. A restriction or jet 42 ls provided between the passages 32 and 33 through which fuel is adapted to flow.

Passage 32 is provided with a branch passage 44 which communicates with the impeller chamber 4e of a pump, indicated generally at 4'I. This pump, as shown, ls of the centrifugal type which includes an iinpeller iii driven by the engine through a shaft 5@ which is suitably connected,

' by any well known means, with said engine which is not shown herein but which rotates said impeller in direct proportion to the R. P. M. of said engine and is adapted to build up an outlet pressure which provides the metering head for the system.

The outlet of pump 4l is connected to a passage 52 which communicates Witha chamber 54 on the side ofl the diaphragm 38 opposite the chamber 34 by way of a metering restriction or jet 56 therein, the pressure of fuel in said chamber 54 being at all times substantially the same as that in the passage 52 posterior to the jet 56 and this pressure will be hereinafter referred to as pressure B or metered fuel pressure.

Chamber 54 has an outlet connected by a conduit 58 with a fuel distributor, indicated generally at 60, and which will'be more fully described ,t hereinafter, The outlet for the chamber 54 is 3 provided with a fitting 82 having a bore within which a flat sidedy or fiuted valve88 is slidably guided, said valve having a conical tip 69 cooperating with a valve seat 18 in said fitting for controlling the discharge of fuel from chamber 54. The end of the valve 88 opposite the conical tip is attached to the diaphragm 38. As shown, said attached end is riveted over at 1| and washerlike spring retainer cups 12 and 14 are disposed on opposite sides of the diaphragm to reinforce the central portion of same. It is to be noted that said spring retainers have their peripheral edge portions turned outwardly, relative to the diaphragm, thus preventing the diaphragm from being cut or otherwise injured thereby and providing means for retaining the adjacent ends of springs 18 and 18 disposed respectively in chambers 64 and 38. These springs 'are preferably light and of substantially the same calibration although they may have other characteristics. Spring 16 reacts between the spring retainer 14 and one wall of the chamber 58 for urging the valve 68 in the opening direction, while spring 18 reacts between retainer 12 and a spring rel tainer 88 disposed in chamber 34, said spring being adapted to urge the valve 68 in the closing direction. The effective force of the springs is adjustable, a screw 82, threadably received in an opening in the casing 36, being provided therefor. It is to be understood that preferably the adjustment is such that the valve 68 is normally slightly open when the engine is inoperative, for a purpose" to be described hereinafter.

The passages 52 and 33 are connected together by conduits 86 and 81. One end of conduit 88 communicates with the passage 62 anterior to the restriction 66 and one end of conduit 81 communicates with the passage 33, there being a restriction or orifice 88 provided between said conduits 86 and 81. It is to be noted that the fuel pressure in conduit 86 is at allItimes substantially the same as the pressure in that portion of the passage 52 anterior to jet 58 and the pressure in said conduit and passage will be hereinafter referred to as pressure C. The pressure in passage 81 will, of course, be the same as that in passage 33 or pressure A.

Means for varying the effective size of' orifice 88 comprises a valve 92 connected to adiaphragm 94 by any well known means. One side of the diaphragm is subjected to pressure C. The diaphragm forms one wall of a chamber 98 formed in a housing 98, said chamber being connected by a conduit |88 to a source of eng/ine charging pressure. As shown, said conduit communicates with the induction passage posterior to the throttle valve I8. However, if a supercharger is used, conduit |88 is connected to the engine manifold posterior to the supercharger. A spring |02, in chamber 96, reacts between one wall of said chamber and a spring retainer |84 and is adapted to urge the valve in the closing direction, said spring being so calibrated that the valve 92 will be normally closed. A boss |66 is provided to limit opening movement of valve 92. If desired, means may' be provided, similar to the screw 82 arrangement, for adjusting the force of spring |82.

With the foregoing arrangement it will be apparent that the valve 92 is controlled by fuel pressure C and the combined opposing force of spring |82 and the pressure in chamber 86.

It is also to be noted that the pressure in branch passage 44 is at all times substantially the same as that in passage 32 and the pressure in said passages will be hereinafter referred to as pressure D or pump inlet pressure.

OPERATION g During normal operation fuel is supplied under pressure to the inlet M of the centrifugal pump 41 by means such as the fuel pump 28 although other means may also be employed to supply fuel to said in'et 44. Fuel received by pump 41 is discharged under an increased pressure into passage 62 from which it flows through metering orifice 68 to chamber 54, past valve 68 which is opened by the pressure of fuel in chamber 54 acting on diaphragm 38, into conduit 58.

Due to the inherent characteristics of the centrifugal pump 41, the pressure C at the outlet of pump 41 will be greater than the pump inlet pressure D by an amount which is directly proportional to the square of the speed of the pump and consequently directly proportional to the square of the engine speed.

For purposes of illustration, during operation, with the valve 92 in a partially open position, fuel at pressure C will flow through the calibrated restriction 88 into passage 81 and thence into passage 33, then through orice 42 to the pump inlet u. As a consequence the pressure in passage 33, herein referred to as control pressure A, will be of a value intermediate the fuel pressure C and pump inlet pressure D, and its value relative to the pressures C and D will depend upon the effective size of orifice 88 relative to the area of A orifice I2. For any fixed setting of valve 92, pressure A will remain greater than pressure D and less than pressure C by amounts representing constant percentages of the difference between pressures C arid D. Thus, if orifice 88 has an effective area equal to orifice 42, pressure A will remain substantially half way between pressures C and D irrespective of variations in speed of pump 41. It therefore follows that the differential between pressures C and A will likewise vary as the square of engine speed, for a fixed setting of valve 92.

Since the springs 16 and 18 are substantially in balance, except fory considerations hereinafter explained, the lpressure of the fuel in chamber 64, referred to herein as metered fuel pressure B, will be maintained equal to control pressure A. In the event pressure B should tend to exceed pressuie A the valve 88 will tend to open to allow the escape of additional fuel to the nozzle and consequent lowering of pressure B, and the reverse action will occur if B tends to be less than A. It is thus clear that the difierence between pressure C and pressure B likewise will vary as the square of the engine speed for a given setting of valve 92.

As is generally known, the quantity of fuel which will fiow through a given size metering orifice such as metering jet 56 will vary in proportion to the square root of the differential in pressures C and B on opposite sides of the ori'ce, and since this differential varies as the square of the engine speed, it will be apparent that the quantity of fuel flowing through orifice 58 for a given setting of valve 92 will vary directly as the engine speed;

In view of the fact that the weight of air flow to an engine at a given manifold pressure varies substantially in direct proportion to the engine speed, except for variations caused by variables such as exhaust back pressure and intake air and exhaust gas temperatures which may be compensated for as described in the copending application of 'Wirth and Barfod, Serial No. 607,290, filed July 27, 1945, the device here described will supply fuel to the engine in accordance with the air flow thereto.

If at a given engine speed the manifold or engine charging pressure is increased, the weight of air supplied to the engine will likewise increas, and the quantity of fuel supplied to the will provide a substantially constant mixture richness, but by introducing an extraneous factor to effect variations in the position of valve 68 as by varying the area of the metering orifice 88, any fuel metering characteristic may be obtained. Means other than pump 41 must also be used to create a pressure in passage 52 winch varies as the square of engine speed.

AccsLssA'rIoN Davies Means for providing a supply of acceleration fuel for enriching the mixture during periods of acceleration comprises a control unit indicated generally at H0. A fuel passage 2 is connected with the passage 52 and a fuel passage |44 is connected with the passage 58. The flow of fuel between passages ||2 and ||4 is controlled by a the valve 68 will open to permit discharge of fuel to the engine at a greater rate such that the pressure B will be reduced .to equal new pressure A. In other words. reducing pressure A reduces pressure B and thereby increases the differential between fuel pressure C and metered fuel pressure B. Consequently, fuel is delivered through orifice 66 at a greater rate to compensate for the increase the valve in an open position. Under these con-v ditions the engine is supplied with an economical mixture.

When the engine is operating at a relatively high speed, whereat it is desirable to enrich the mixtureithe pressure C will be at a relatively high value. However the manifold suction will be substantially lower than at idle so that the combined forces of pressure C and the manifold suction in chamber 96 will be insuficientto maintain the valve 92 open. Upon closing of said valve 92 lpressure A will drop and pressure B'will rise and effect further opening of the valve 68' to provide the additional fuel required for power enrichment.

If desired, other arrangements may be provided. for obtaining various desired fuel to air relationships in accordance with engine variables.

Provision may be made for enriching the idling fuel mixture as is desired. One means for effecting idle enrichment is to adjust valve 68 so that it is normally slightly open. Thus the fuel metering differential pressure required to balance the diaphragm valve assembly is increased. Then at low differential pressures, corresponding to idle operation, the arrangement is of material effect in producing a relatively large percentage i11- crease in fuel flow, thereby providing the desired rich mixture at idle. However at high differential pressures the arrangement has a .negligible effect and has substantially no e'ect on the richness of the fuel mixture which is maintained at in air flow which instigated the change in pressure valve ||6 which controls the effective area of an orifice ||8 between said passages !I2 and H4. The valve ||6 is profiled to permit the passage of fuel thereby and is slidable in a plug |20 in which the orifice ||8 is formed. One endy of the valve ||6 is secured to a diaphragm |22 which forms one wall of a chamber |24 with which the passage ||2 communicates, fuel from said chamber |24 being adapted to flow past said valve ||6, when open through the orifice ||8 and into the passage ||4.

The unit ||0 is provided with a second diaphragm I 26 which is of larger area than diaphragm |22 and which forms one wall of a chamber |28,

another wall of which is formed by the diaphragm for urging the valve in the closing direction, said lug |38 forming a one-way connection between the diaphragm |26 and said valve. A conduit |40 is connected with the conduit |00 for transmitting engine charging pressure to the chambers |28 and |30, the chamber |28 communicating with said conduit |40 by means of a relatively large passage |42 whereas the chamber |30 communicates with said passage |4'0 by means of a relatively small orifice |44. 4

Normally the pressures in chambers |28 and |30 are substantially the same and spring |32 is adapted to maintain the Vvalve in the closed position against the pressure of fuel in cham-ber |24 exerted upon diaphragm |22. Assuming the throttle valve i8 is suddenly opened, as for acceleration purposes, the pressure in chamber |28 will rise faster than that in chamber |30, due toy the difference in effective areas of passages |42 and |44 thereby compressing spring |32 and moving the lug |38 away from'the adjacent end of valve ||6. The pressure of fuel at pressure C on diaphragm |22 then will urge said diaphragm to the left, as shown in the drawing, and effect opening of the valve H6. Upon opening of said valve an additional quantity of fuel will be supplied to the conduit 58 to enrich the mixture for acceleration purposes. Assuming the throttle I0 remains' in the position to which it has been moved the pressures in chambers |28 and |30 will shortly equalize and spring |32 will then effect closing of valve I6.

If desired, a fuel connection 5| may be provided between passages 52 and 33, said passage 5| having a manually adjusted needlevalve 53 controlling the eective area of a restriction 55 in said passage With this arrangement the fuel .ys'tem mf'ay be adjusted for various installations.

FUEL DISTRIBUTION Fuelv from the conduit 68 is distributed to a plurality of conduits |48 by the distributor 50. The conduits |48 carry the distributed fuel to respective discharge nozzles |50 located in the intake manifold |52 of the engine. For purposes of illustration only the manifold |52 is shown as having four outlets |54 (it may have any other number required by the particular installation) which deliver fuel and air to the various intake ports of the engine which are controlled -by inlet valves, not shown. As shown, the nozzles |50 are so arranged that their discharge `ends are adjacent the outlets |54 and are axially-allgned with said outlets.

Referring' now to the enlarged view of the distributor 60, shown in Figures 2, 3 and 4, saidl distributor comprises a casing |56 having a. cover member |58 secured thereto =by means of screws |60 or the like. Within the casing is a rotor |62 a passage |14 therein, one end of which commu-Al nicates with one end of the rotor in such a manner as to be in constant communication with an axially arranged inlet port |18 which is connected with the conduit 58. The passage |14 moreover extends through the rotor to a point adjacent the periphery thereof and has an outlet |80, in the face opposite the inlet port |16, which is adapted to register with outlet ports |82, best showndn Figure 3. As said rotor is rotated the ports |82 successively communicate with outlets |84v which are connected with therespective conduits |48 leading to the various fuel nozzles. An annular seal |85 received in a groove in cover member |58 prevents leakage of fuel therepast between said cover |58 and the rotor |62.

In operation as the rotor is rotated the outlet |80 of the rotor passage |14 communicates successively with the respective ports |82 to permit the passage of fuel from conduit 58 to therespective nozzles |50 during the time the respective intake valves are open and said fuel is cut oil from said nozzles as the intake valves close. Thus an improved fuel distribution system is provided which supplies fuel to the engine in a uniform manner.

I FIGURE 5 Another type o f fuel distributor is shown in Figure 5 and comprises a casing |88 having respective outlet passages |90, the inlet ends of said passages communicate with a rotor chamber in which a rotor |82 is disposed and which completely fills said chamber. Fuel from the conduit 58 is supplied to the central portion/ |84 of the distributing passage |96 in said rotor and said passage extends to the peripheral surface of the rotor. As the rotor is rotated the discharge end |98 of said passage |96 progressively supplies and cuts off fuel to the passages |80 effecting substantially the same cycle of fuel distribution as that of the arrangement shown in Figures `2,8 and 4.

Nozznns clined surface 204 disposed adjacent a similarly inclined surface of a body portion 206. The parts 208 and 288 are secured together by a member 208 having an internal shoulder which engages the shoulder portion 202 and a threaded end portion adapted to be threaded onto the adjacent end of the body 208. If desired a gasket 2|0 may be interposed between the inclined surfaces of the portions 282 and the body member 205. The body 206 is provided with an internal bore 2|I in which is press tted a profiled guide 2|2. The guide is provided with a central passage in which a movable valve member 2 I4 is slidable, said valve member having an enlarged end 2|6 adapted to control the outlet port 2|8 of the nozzle. The inner end of the valve member 2|4 extends be yond the guide 2|2 and is provided with a washer 220 secured on the member 2|4 by the riveted over head 222 of a reduced portion of said member 2l4, there being'a small washer 224 .interposed between the riveted over headl and the washer 220. A calibrated spring 226 reacts between the adjacent end of the guide'2l2 and the washer 220 for urging the valve in the closing direction. Fuel enters the passage 228 of the stem 208, ows through a restriction 230 into a passage 282, thence through the bore 2|0 and out the discharge orice 2|8 when the valve 2|6 is open.

With the foregoing nozzle arrangement fuel may be supplied at a relatively low pressure, for example, about three pounds and said pressure is sufllcient to open the valve 2|'6k to permit the discharge of the fuel into the intake manifold. When the fuel is cut off from the nozzle the spring 226 will eilect a sharp cut off of the fuel flow.

The nozzle shown in Figure 8 comprises a body portion 240 having a threaded inlet 242. A .reduced portion 244 is threaded to provide means for securing the nozzle in the intake manifold and a further reduced portion 246 is adapted to extend inwardly of the manifold whereby the discharge end 248 will be located adjacent the respective outlet of said manifold. The inlet 242 communicates with a bore or fuelv passage 250 which extends through the parts 244 and 246 of the nozzle and terminates at tl.; discharge eng 248. A restriction 252 is provided in the bore 25 The nozzle shown in Figure 9 is similar in construction to that shown in Figure 8 except for the omission of the restriction 252.

It is preferable to use a nozzle having an opening or fuel discharge passage which is correlated with the pressure of fuel prevailing in the fuel system. For example, a restricted passage such as shown in Figure 8 may be used to advantage in a fuel system wherein the fuel pressures are relatively high, while an arrangement such as shown in Figure 9 may be used in a system wherein the fuel pressures are lower.

From the foregoing it will be apparent that various changes may be made in the various parts of the invention without departing from the principles thereof and it is contemplated that any such arrangement properly falling within the scope of the subjoined claims may be used.

We claim:

1. A fuel supply system for an internal combustion engine comprising -a conduit adapted to connect a source of fuel with the engine; means for creating a fuel pressure in and effecting a flow of fuel through said conduit, the quantity of which will vary directly as the engine speed; means for controlling said flow; means adapted to contain a control pressure developed by the first mentioned means and acting on the second mentioned means for influencing the functioning thereof; and means, including a valve, for varying the control pressure, said means being so constructed and arranged that at engine speeds below a predetermined value the valve is open to provide an economical mixture to the engine, and at speeds above said value said valve is closed to provide for -power enrichment.

2. The invention defined by claim 1 wherein said valve is controlled by engine charging pressure and by fuel pressure.

3. The invention defined by claim 1 wherein the last mentioned means is controlled by manifold vacuum and by fuel under substantially the full rst mentioned pressure.

4. The invention defined by claim 1 wherein there is also a manually adjusted screw valve for regulating the control pressure.

5. In a fuel system for an'internal combustion engine: a source of fuel; a conduit connecting said source of fuel with the engine; a metering orifice in said conduit; means, having an inlet and an outlet, for supplying fuel to said metering orifice at a pressure varying in response to variations in engine speed; means for controlling the fuel flow posterior to the metering means; means adapted to contain a control pressure developed by the first mentioned means and acting on the vsecond mentioned means for influencing the functioning thereof; and means, including a.v

valve, for varying the control pressure, said means being controlled by engine charging pressure and by fuel pressure.

6. The invention defined by claim 5 wherein the last mentioned fuel pressure is substantiallyy equal to the first mentioned pressure.

'7. In a fuel system for an internal combustion to fiuid pressure posterior to the metering means and t-o the intermediate pressure acting in opposition to said fluid pressure; a fuel distributing device having an inlet and a plurality of outlets:

' a conduit connecting said inlet with the fuel lflow control means posterior thereof, said distributor having a rotor operated in timed relationship with said engine valves; discharge nozzles discharging adjacent the outlets of the manifold; and conduits connecting said nozzles with the respective distributor outlets.

l0 the axis of the rotor adjacent one end` of said rotor; circumferentially arranged outlet passages; anda passage in the rotor adapted to be connected with the fuel inlet passage at all times and to intermittently supply fuel to the outlet passages as said rotor is actuated.

9. The invention defined by claim 7 wherein the distributor includes a chamber; a rotor in said chamber; a closure for said chamber having a fuel inlet passage substantially centrally disposed therein; circumferentially arranged outlets; aX

passage 'in the rotor adapted to be connected with the fuel inlet passage at all times and to intermittently supply fuel to the outlets as said rotor is actuated; and a seal between the closure and the rotor to prevent leakage of fuel between said closure and rotor from the adjacent ends of the passage in the closure and the passage in the rotor. i, n

10. In a fuel system for an internal combustion engine having an intake manifold with yan outlet; a source of fuel; a fuel conduit having a metering restriction therein connected with said source of fuel; means in said conduit for creating across said restriction a fuel head adapted to vary in accordance with the square of engine speed; means forcontrolling the fuel flow through said conduit; means adapted to contain a control` pressure developed by the first mentioned means and acting on the second mentioned means for influencing the functioning thereof; a fuel discharge passage; and a fuel nozzle connected with said discharge passage and adapted to discharge fuel adjacent the manifold outlet.

1l. The invention defined by claim 10 wherein said nozzle includes a valve which is spring loaded in the closing direction.

8. The invention defined by claim 7 wherein i the distributor comprises a casing enclosing a chamber; a rotor in said chamber; a fuel inlet passage in one wall of the casing and aligned with 12. The invention defined by claim 10 wherein there is a restriction in thevfuel passage of the fuel nozzle.

13. In a fuel system for an internal combustion engine having inlet valves: a source of fuel; a conduit connecting said source of fuel with the engine; means for creating a fuel pressure in and effecting a flow of fuel through said conduit, the quantity of which will vary directly in accordance with engine speed; means for controlling said flow; means adapted to contain a control pressure developed by the first mentioned means and acting on the second mentioned means for infiuencing the functioning thereof; means, including a valve, for varying the control pressure, said means being so constructed and arranged that at engine speeds below a predetermined value the valve is maintained open to provide an economical mixture, and at s peedsabove said value said valve is closed to provide for power enrichment; and fuel distributing means having an inlet; a conduit connecting said inlet with the fuel flow control means posterior thereof, said distributing means having a rotor operated in' pressure.

15. A fuel metering device for an engine comprising a. fuel conduit for delivering fuel to said engine; an impeller, a metering orifice, a disl charge valve, and fuel distributor, in series in said conduit, said impeller and distributor being adapted to be driven by the engine; and a plurality of fuel discharge nozzles adapted to receive fuel intermittently from said distributor and to discharge said fuel into said engine.

16. A fuel metering device for an engine comprising a fuel conduit for delivering fuel to said engine; an impeller, a metering orifice, a discharge valve, and a fuel distributor, in series in said conduit in that order, said impeller and distributor being adapted to bev driven by the engine; and a plurality of fuel discharge nozzles adapted to receive fuel from said distributor at a pressure varyingin accordance with engine speed and to discharge said fuel into the induction system of said engine.

17. A fuel metering device for an engine comprising a source of fuel at a, substantially constant pressure; al conduit for connecting said source with said engine; an engine driven imp peller, a metering orifice, a discharge valve, and a fuel distributor, in series in said conduit. said impeller and distributor being .adapted to be driven by the engine: and a plurality of fuel discharge nozzles adapted to receive fuel inter? mittently from said distributor and to discharge it in the intake manifold of said engine.

18. A fuel metering device for an engine comprising a source of fuel at a substantially constant pressure; a conduit connecting said source with said engine: an impeller, a metering orifice, a discharge valve, and a fuel distributor, in series in said conduit, said impeller and distributor adapted to be driven by said engine in accordance with the speed thereof; and a plurality of fuel discharge nozzles adapted to receive fuel intermittently from said distributor and to discharge said fuel in said engine.

19. A fuel metering device for an engine comprising a source of fuel at a substantially constant pressure; a conduit connecting said source with said engine; an impeller, a metering orifice, a discharge valve, and a fuel distributor, in series in said conduit in that order, said impeller and distributor adapted to be driven by said engine in accordance with the speed thereof; a plurality of fuel discharge nozzles adapted to receive fuel intermittently from said distributor at a pressure varying with engine speed and to discharge said fuel in the induction system of said engine; a by-pass around said impeller having two restrictions therein to provide a control pressure intermediate the pressure on either side of said impeller for regulating said discharge valve; and a valve for varying the effective area of one ofy said restrictions.. thereby to vary said control pressure. e

EMIL O. WIRTH. FREDERIK BARFOD.

REFERENCES CITED /The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,597,787 Hausser et al Aug. 31, 1926 1,802,848 Summers Apr. 28, 1931 1,971,187 Jacobson et al Aug. 21, 1934 2,126,709 Alden Aug. 16, 1938 2,348,008 Hunt May 2, 1944 2,374,844 Stokes May 1, 1945 FOREIGN PATENTS Number Country Date 429,682 Great Britain June 4, 1935 523,895 Great Britain 1- July 25, 1940 

